POLICE had to quell unruly fans outside the Supreme Court in Kingston on March 13th, after a jury pronounced Adidja “Vybz Kartel” Palmer (pictured) guilty of murder. Although the death penalty is unlikely to be applied, the self-proclaimed “World Boss” of Jamaican music faces up to 50 years in prison when he is sentenced on March 27th.Along with three associates, Mr Palmer was found guilty of butchering Clive “Lizard” Williams in August 2011, for failing to return two guns. (His lawyers say he will appeal.) He has been behind bars since September 2011, charged originally with two separate murders. In July last year, he was found not guilty of murdering a 27-year old music promoter, Barrington “Bossy” Burton. The “Lizard” trial started in November, and this time he was less fortunate.

The guilty verdict took many people by surprise. The police produced incriminating text messages and video recordings, among them a text saying Mr Williams’s body was chopped up “fine fine… As long as u live dem can never find him.” But the defence argued that this digital evidence was unreliable: a seized BlackBerry phone appears to have been switched on and used while supposedly in a secure evidence locker; and a back-up CD with telecommunications data went missing. On the day of the verdict, a juror was arrested for allegedly attempting to bribe his fellow jurors to plump for a “not guilty” verdict.

Mr Palmer’s fall from grace would be big news on its own. He is a big star in the world of dancehall, the successor to Jamaica’s earlier reggae music. Before his arrest, Mr Palmer attracted high-profile corporate sponsors such as LIME (Landline, Internet, Mobile and Entertainment), the local affiliate of a British telecommunications company, Cable and Wireless. His violent lyrics, said apologists, were just word-play. In court, he tried to distance himself from his bad-boy image: "My Lord I bleach my skin My Lord, and I am heavily tattooed My Lord, but that is merely superficial, My Lord. That is part of the persona of Vybz Kartel not Adidja Palmer.”

But the verdict fits into a broader pattern. Other Jamaican entertainers have hit trouble. Mark “Buju Banton” Myrie is in a Florida prison, serving a ten-year cocaine trafficking sentence; his appeal is before the courts. Desmond “Ninjaman” Ballentine was charged with murder in 2009; he is on bail, with a trial set for April. A string of others have been charged with, and in some case convicted of, rape, drug, domestic violence, firearms or “lottery scam” offences (in which criminal gangs fleece elderly Americans of their savings).

In September the police commissioner Owen Ellington in September told the Jamaican parliament that “intelligence and evidence” show that some entertainers have been co-opted by criminal gangs, and use songs to promote killing, intimidation and a code of silence that allows wrongdoers to operate at will. Academics link violent lyrics to the marginalisation of young working-class males. On March 7th Parliament passed legislation prohibiting any “audio, visual or audiovisual communication” that promotes killing or violence. There is plenty to ban. “They’ll have to keep on locking them up,” says one Jamaican musician.